It is precisely in the area of biotechnology that in recent years there has been an increase in the search for automation solutions for safe and efficient processing, particularly in the case of a large number of samples that arise, for example, in HIV virus monitoring. In this connection there is increasing demand for fully automatic, high-throughput work stations, which process a very large number of samples in the shortest possible time, wherein increasingly additional manual input is dispensed with, while at the same time the smallest quantities of biological materials need to be detected.
However, the currently popular robotic systems have a fundamental problem when working with biological material, especially in the area of molecular biology and/or diagnostics. Since the samples are normally processed on a flat body (such as a rack) whereby the individual sample vessels stand open next to one another, contamination of mainly neighbouring samples occurs during processing, principally by aerosol formation, but also repeatedly through mechanical transfer of sample material.
To avoid such (cross-)contamination a number of add-on modules and/or consumables for robotic systems are disclosed in the state of the art. Thus, for example, caps or, as disclosed in the utility patent specification DE 200 06 546 U1, cover pads to protect prepared, upwardly open reaction vessels on flat bodies. This type of covering, however, only protects the samples of a rack, for example, during transport and/or during storage. However, contamination continues to occur during processing of the individual samples on the rack.
Furthermore, cross-contamination rates can only be reduced but not fully eliminated by the use of sterile consumables known from the state of the art, for example specially coated disposable pipettes and/or disposable filter tips. Thus contamination principally in the ppm range remains a fundamental problem (for example in the area of PCR diagnostics, where single molecules are detected).
Furthermore, methods are known in which, as disclosed for example in the European patent specification EP 0011327 B1, the aqueous solution incorporates water-soluble compounds to avoid aerosol formation. However, as these mix with the sample liquid and can possibly even change them or lead to undesirable side reactions their use is extremely disadvantageous and, in PCR diagnostics in particular, not conceivable.
In addition a plethora of enclosure possibilities have been developed for protection against contamination of the samples, for example covers, septa and/or filters, etc., for one or more sample vessels. However, these have disadvantages in handling especially in the area of automation since, for example, opening and closing the closures, etc., is very time consuming, and depending upon the closure system not very feasible mechanically. Besides, there is still the risk that aerosols formed in the sample vessel can escape during processing and in that way on opening the neighbouring sample vessel in the next step that sample can be contaminated with sample material.
Moreover, sample vessels with septa and/or thin filter material are not flexibly applicable in each robotic or automatic pipetting system since only a small number of pipette tips and/or pipette needles are suitable for such sample vessels.